1. Field of the Invention
The present invention relates to an improved apparatus and method for cooking a starch and water solution to form cooked starch and then dispensing the cooked starch into a commercial laundry machine. More particularly, the present invention relates to an improved commercial starch cooking apparatus and method wherein the starch and water solution and a heating source are passed through a heat exchanger for cooking to form cooked starch, which is then delivered to one or more commercial laundry machines. The present invention cooks and dispenses starch in single batches or multiple single batches; starch may be dispensed in a continuous stream subject to the heat exchanger size and rate of flow of the constant heating source.
2. Prior Art
In the dry cleaning industry today, there are various starch cookers for cooking a mixture of corn starch and water for the purpose of starching dress shirts, blue jeans, khaki pants, tablecloths, cotton napkins and other items of clothing. Ideally, the mixture of corn starch and water should reach a cooked temperature of range of 180 degrees Fahrenheit to 205 degrees Fahrenheit, preferably the mixture should be cooked to a temperature range of 190 degrees Fahrenheit to 195 degrees Fahrenheit. If the starch mixture is cooked too hot, the chemical and physical makeup of the starch solution continues to change causing, the mixture to form a glue-like slurry.
Presently, three (3) main methods for cooking starch are used. A first method utilizes an open pan batch method where the starch is hand poured into the open pan cooker. This method is extremely dangerous and very labor intensive. A second method uses an open pan batch to cook the starch, but the starch is fed into the open pan cooker using a pump and pipe. This method results in high maintenance costs due to starch build-up in the pump and pipes, and thus requires continuous, labor intensive cleaning. In addition, this method demands a high level of attention from the operator. A third method used today is the steam-injected, closed-batch method utilizing a pump and pipe for feeding starch into the cooker. This method relies on direct steam injection from a boiler; however, boiler treatment compounds, along with rust, calcium and other contaminates are also injected with the steam into the starch. These undesirable contaminants adhere to the clothing items. Further, this method uses a violent mixture of steam and starch solution which cannot be accurately controlled resulting in incomplete starch cooking.
Mitchell, et al. (U.S. Pat. No. 5,437,169) discloses a starch cooking device that utilizes a tank float device to open and close a water supply line. The float is immersed in the starch and water solution causing starch build-up on the float and pipes thus requiring continuous, labor intensive cleaning. Mitchell also discloses using direct steam injection to both cook and agitate the starch and water solution. This may result in lumpy starch, thus causing uneven starching of garments. Furthermore, as previously mentioned, direct steam injection may result in contaminants mixing with the starch solution causing contamination and discoloration of garments.
Mitchell, et al. (U.S. Pat. No. 5,680,663) discloses a starch cooking device that utilizes a tank float device to open and close a water supply line. The float is immersed in the starch and water solution causing starch build-up on the float and pipes, thus requiring continuous, labor intensive cleaning. Mitchell also discloses using direct steam injection to both cook and agitate the starch and water solution. This may result in lumpy starch, thus causing uneven starching of garments. Furthermore, as previously mentioned, direct steam injection may result in contaminants mixing with the starch solution causing, contamination and discoloration of garments.
Mitchell, et al. (U.S. Pat. No. 5,901,584) discloses a starch cooking device having a starch cooking valve for direct steam injection. In this patent, a starch solution is mixed with a direct injection of steam in the starch cooking valve to form cooked starch. This patent also utilizes a hopper and auger assembly to agitate the starch and water solution. As previously mentioned, the reaction between the starch solution and a direct injection of steam is violent and may result in the incomplete cooking, of starch. Further, using an auger to agitate the starch and water solution may result in the auger tunneling through the starch, leaving air pockets or tunnels in the starch and water mixture.
Boling (U.S. Pat. No. 5,964,950) is directed towards a starch cooking device having a single vessel or mixing, cooking a starch solution. MS patent uses a recirculating flow line with a gear pumping arrangement to break up lumps in the starch. This patent requires a user to add starch to the vessel for cooking. As discussed above, this hand pour, open batch method is extremely dangerous for commercial applications, and is also very labor intensive.
Mitchell, et al. (U.S. Pat. No. 6,507,966) also discloses a starch cooking device that uses a hopper and auger for mixing a starch and water solution and a steam valve for direct steam injection for cooking the starch and water mixture. Again, the reaction between the starch solution and a direct injection of steam is a violent reaction which may result in the incomplete cooking of starch. Also, using an auger to agitate the starch and water solution may result in the auger tunneling through the starch, leaving air pockets or tunnels in the starch and water mixture.
Accordingly, it is desirable to produce a starch cooking device that completely cooks a starch and water solution without the addition of any contaminants and other impurities.
It is also desirable to form a starch cooking device that utilizes a flushing system to eliminate starch build-up which otherwise requires labor intensive cleaning.
It is desirable to have a starch cooker that is predominantly automated using a programmable computer to control mixing, cooking and flushing procedures.
It is also desirable for a starch cooker to deliver multiple levels of starch to a commercial laundry machine depending on the user's needs.
It is further desirable for a starch cooker to have a closed system in which the starch and water solution and the heating source are contained in separate chambers, thus cooking the starch without any possibility of contamination during the cooking process.